2000 Dodge Dakota shift from 4 to 5 noise from engine

Check your u-joints. They are most likely worn and your drivehaft has a little bit of moving room which is why you would get a lot of vibration at high speeds. Had the same problem where I thought it was in the engine compartment as well but I consulted Chiltons manuel and sure enough it was the u-joints. Easiest way to check is to lay under ur truck and grab the driveshaft and attempt to rock it from the side to side. If it moves then replace u-joints and go from there. BEST OF LUCK